Introducing analysis of means to medical statistics.

Statistical hypothesis testing involving the comparison of three or more means and/or proportions is a frequent undertaking in medical statistics. For comparison of means, analysis of variance is a common choice and for comparison of proportions, χ(2) tests are common. However, both these approaches have important limitations which include the need for post hoc testing to identify the unusual group(s) without an integral graphical device to present the final results. These limitations are elegantly overcome by the analysis of means, which is widely used in industrial statistics, and illustrated here using means and proportions.